How Sandy could cause lots of coastal damage: The science

[RobertEarl]

Think of Sandy as a big ball of moving air spinning to the left. A ball of air at speeds averaging 50 miles an hour. At the surface of the ocean, this air moves water in the same direction. This direction is from east to west.

Now picture the coast from NJ up and along New York's Long Island, as a corner. A corner into which the air is blowing all this water. Bottling it up, as it were, up against the coastal corner leaving it nowhere to go but climb the walls.

And, Sandy, being a low pressure system, is an air mass that is rising. As the air rises think of it as sucking at the ocean surface. It actually may suck the surface up as much as two feet.

Put all this together and as the storm gets closer to land, and if it is high tide by the moon, the resulting water could gain as much as 13 feet above what is normal levels.

It could, if it all comes together at once, be like a Tsunami.

The weather service people, rightly so, can imagine such a scenario. That is why they are warning people so forcefully. If you are less than 13 feet above normal sea level, you could be drowned by this storm.

[KT2000]

1. does this mean that

the "rain" that occurs during the hurricane will be salt water that was sucked up from the ocean?

[Hissyspit]

2. No:

http://www.komonews.com/weather/blogs/scott/46000687.html

Do hurricanes rain salt water? And why isn't our own rain salty?
By Scott Sistek Published: Sep 14, 2010 at 11:08 AM PDT

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When a hurricane rages in the Gulf of Mexico or Atlantic Ocean, you might think since it's churning along over such a large area of salt water, that its accompanying rain is full of salt? Same goes for our rain from storms born in the salty Pacific Ocean -- why doesn't it rain salt water here?

But it doesn't. In fact, all the rain -- no matter where in the world it is -- is freshwater (mostly. See below).

Why? It has to do with the evaporating process. When water evaporates from the ocean, only the pure H2O molecules are involved -- it's basically energy turning the water from liquid state to vapor state. The salt particles are left behind.

I'm not an oceanographer, but I would assume that means when you've got a really big storm, like a hurricane, taking in a lot of moisture from the warm Gulf/ocean waters, the salt content of the water in its wake is probably a miniscule higher, but negligible compared to the vast volume of the water.

Now that said, there are a few ways to get a salty rain, but it doesn't involve evaporation.

Communities along the coast deal with salt and rust from wind blowing in spray off the ocean. In that case, it is salt water because you are transporting water droplets directly from the water. Same with hurricanes and their storm surges and wind-whipped spray off the surf -- that is all salt water.


http://usatoday30.usatoday.com/weather/resources/askjack/archives-hurricane-science.htm

Q: A hurricane "picks up" saltwater over the ocean, but rains fresh water. Where does the salt go?

A: The process by which a hurricane "picks up" water over the ocean is called evaporation. That is, heating by the sun makes saltwater warm enough that molecules of water leave the liquid state and become water vapor in the atmosphere. The salts that are diluted in the water are left behind, making the remaining ocean water even saltier. The water vapor condenses to form clouds within the hurricane and eventually precipitates out of the storm as fresh rainwater.

[KT2000]

3. thanks for the good info!

your effort is appreciated

[RobertEarl]

4. Boston people are you flooded yet?

How about those at the west end of Long Island Sound?

Edison NJ?

All these locations are getting sustained winds of 40mph+ and the water will be piling up in those east facing areas.

Looks like NYC is NOT going to get too much water piled up.

Further south, along the Jersey shore, inland to Philadelphia is where the center of the storm will land. To the southwest of there will be the strongest winds. But the winds will be offshore, from the west to the east. Meaning the water will be blown away from land. No flooding, except maybe from rainfall over the next week.